The QuickFinder® has a red, yellow, and green light indicating when it is okay to cut and when it is not safe. Start at the base of the nail, furthest from the tip, and slowly move toward the tip of the nail. The QuickFinder® needs to sense the quick first to know when it is no longer there. Slowly move the QuickFinder® tool closer to the tip of the nail, the color will change to yellow and then green. When the light is green it is acceptable to cut the nail. Once the light it green clamp down on the handle and trim the nail.